Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
  • B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
  • B27K3/002—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process employing compositions comprising microorganisms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
  • B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
  • B27K3/02—Processes; Apparatus
  • B27K3/0207—Pretreatment of wood before impregnation

Definitions

• This invention relates to a method for biologically controlling the discoloring of wood products by fungi.
• the pitch degrading fungus is preferably inoculated onto wood chips and allowed to grow, usually for from 4 to 30 days.
• a white/colorless growing fungus is used for pitch degradation, it was reported that such fungi could improve the color of the treated chips and reduce bleaching requirement by reducing the apparent growth/amount of blue stain fungi which had naturally infected the wood.
• pitch could be reduced by inoculating the pitch-reducing fungi onto timber prior to chipping or other mechanical action in the process of forming pulp, such inoculation taking place at the end of the logs and/or by scoring the logs lengthwise and inoculating into the scores.
• the color effects of inoculating logs in such fashion on the later growth of naturally infecting staining fungi in the logs themselves was not studied or reported.
• Fungi which have been described as useful for pitch degradation generally penetrate the wood, creating narrow voids and openings which appear related to other advantages observed in pulping wood treated with such fungi. However, such treatments have little or no effect on the cellulose, hemicellulose or lignin content of the wood.
• the log lengths may be treated with an insecticide effective to suppress the bark beetles.
• Lengthwise areas which have been debarked in tree-falling or handling may also be inoculated with a white/colorless growing fungus.
• the logs may be scored lengthwise, preferably at intervals of 8 to 20 inches around the log circumference, and the white/colorless growing fungus inoculated into the scoring which generally will be carried out to a depth sufficient to substantially reach the under-the-bark wood. If and when logs are to be debarked, and then stored, it is within the scope of the invention to treat the entire debarked surface with the white/colorless growing fungi to protect against staining fungi.
• Such inoculation desirably takes place no more than two weeks after the structural wood is cut from its log source, preferably in no more than one week, more preferably in no more than 4 days and most preferably in no more than 2 days.
• Such treatments are particularly useful to inhibit staining when the structural wood is stored and/or shipped for long periods in environments where staining fungi may be present, such as in ships or trucks which had previously carried infected wood forms such as logs, wood chips and the like.
• the more preferred fungi for use in the invention are white/colorless growing fungi of the fungal classes Ascomycetes and Deuteromycetes as taught in the aforementioned published European Application No. 0470929A2 which contains a disclosure similar to U.S. application Ser. No. 657,581, filed Feb. 19, 1991, now abandoned, which is the parent application of U.S. Pat. No. 5,476,789, the disclosures of which being incorporated herein by reference.
• Such fungi involve a variety of genera which comprise genera classified in the sub-class Ophiostomatales as well as genera including the imperfect states associated to Ophiostomatales.
• Ophiostomatales genera include without limitation Ceratocystis, Ceratocystiopsis, Graphium, Leptographium, Ophiostoma, Phialocephala and Sporothrix as defined with reference to the generic concepts stated in Harrington T.C., "New combinations in Ophiostoma or Ceratocystis species with Leptographium anamorphs", Mycotaxon, 1987, 28:39-43 and in "Leptographium Species, Their Distributions, Hosts and Insect Vectors", Harrington T. C. & Cobb F. W., 1988, pages 1-39, APS press, St.
• Preferred fungi are found in the genera Chloridium, Dactylella, Phialophora and Valsa as well as in the genera classified as Ophiostomatales, these latter genera being particularly preferred. More preferably, the fungi are found in the genera Ceratocystiopsis, Graphium, Leptographium and Ophiostoma, this latter being mostly preferred.
• Ophiostoma examples include without limitation Ophiostoma piliferum and Ophiostoma piceae, particularly Ophiostoma piliferum.
• the pitch degrading fungi of Ascomycetes and Deuteromycetes are particularly preferred because they can grow on and into wood over long periods of time without substantially affecting or degrading the cellulose, hemicellulose or lignin content of the wood.
• the Basidiomycetes including particularly the white rot fungi which degrade pitch in wood are also particularly useful since the action of the fungi in degrading pitch avoids metabolic states in which cellulose, hemicellulose and lignin may be attacked, hence allowing such Basidiomycetes fungi to protect against staining fungi over adequate periods of time without adversely affecting the quality of wood as structural wood.
• White rot fungi which degrade pitch and grow very well on non-sterile wood are Schizophyllum commune, Trichaptum biforme, Phanerochaete gigantea and Phlebia tremellosa.
• Staining fungi protected against by the invention involve those which typically penetrate deeply into the wood and which themselves involve the fungal classes Ascomycetes and Deutermycetes, which staining fungi are typically represented by those also known as blue stains. Such fungi reduce pitch as is now known. While we do not wish to be bound by any theory concerning the invention, the beneficial results provided by the invention are probably due at least in part to the ability of the pitch-degrading white/colorless growing fungi to deprive the staining fungi of their primary food source.
• the log ends will be inoculated in no more than two weeks after falling of the tree, preferably in no more than one week, more preferably in no more than 4 days and most preferably in no more than 2 days after cutting down of the tree.
• the particular fungus to be used will be selected in accord with guidelines given herein including growth ability on the particular wood type being treated. As is known, fungi grow to differing extents on different wood types, particularly when the wood is non-sterile. Hence, generally preferred fungi are those which grow well on the wood type of the substrate to be treated.
• Fungi more suitable for particular wood types are generally known from their history of natural growth habit on particular woods.
• Fungi of the genus Ophiostoma for example, infect a variety of wood types and are very commonly found on pine and other woods such as oak, and are particularly preferred fungi for use in the invention.
• More particularly preferred species are Ophiostoma piceae and Ophiostoma piliferum, and particularly the latter.
• Especially preferred strains of O. piliferum which grow white and/or colorless with considerable growth strength or virulence on woods such as pine are those represented by the designation WZ58 when deposited with the NRRL on Jan. 24, 1991 with the Accession No.
• WZ5803D97 when deposited with the NRRL on November 12, 1991 with the Accession No. 18917, said WZ5803D97 also being referred to herein as "D97" and also being represented by the product commercially available under the registered trademark CARTAPIP®97 from Sandoz Chemicals Corporation, Charlotte, N.C.
• said WZ58 and D97 and derivatives, mutants and other white/colorless growing strains of O. piliferum which have at least the characteristics of growth virulence and pitch degradation exhibited by either on sterilized Southern Yellow Pine as described herein (and respectively in published European Patent Application No. 0470929A2 and U.S. patent application Ser. No. 889,796, filed Jun.
• wood types or genera processed by industry for structural woods may be treated in accord with the invention. These include both Gymnosperms and Angiosperms, and in particular both hardwoods and softwoods. Particular classes or types of wood therefore include without limitation conifers, pines, cedars, oak, maple, aspen, firs and birch. Softwoods such as pines generally have high pitch content and are readily colonized by pitch degrading fungi. Hence, they are more susceptible to invasion by pitch degrading staining fungi, but equally more easily treated in accord with the invention. Hardwoods, particularly those with low pitch contents, may in some instances require more thorough or high dose inoculum of the white/colorless growing fungi in order to ensure optimum germination.
• the fungus to be used in the invention may be applied to the log and log ends in any of a variety of forms and ways.
• the fungus may be applied in any inoculum form giving rise to growth of the fungus, for example, in the form of mycelia or spores.
• Such inoculum may also be in liquid or dry form.
• aqueous suspensions of mycelia and/or spores may be used, or the mycelia and/or spores may be dried or lyophilized to produce dry forms. Liquid aqueous forms of dilute or medium concentrations are generally preferred.
• the inoculum of the white/colorless growing fungus may be applied as a powder in dry form or sprayed or smeared by hand when in liquid form.
• the log ends will be completely covered with the inoculum such as by spraying the log ends to run off or smearing a medium concentrated liquid, e.g. of mycelia, over the entire log end (although pith and heartwood are seldom affected by staining fungi).
• a suitable inoculum involves, for example, relatively concentrated aqueous spore suspensions having from 10 5 to 10 10 CFU (colony forming units per milliliter, more usually 10 6 to 10 9 CFU/ml., although more or less concentrated forms may also be used.
• CFUs colony forming units
• the specific activity of mycelia in colony forming units (CFUs) may be determined by homogenizing the mycelia, e.g. for 5-10 minutes, and approximating the number of colonies resulting therefrom in a conventional manner when the fragments are grown on a nutrient substrate to determine the specific activity in CFUs for a given volume.
• Mycelia expressed as CFU will be used in similar activity concentrations to those of spores as given above. However, mycelia mats may also be simply dewatered and used as such as inoculum as demonstrated herein.
• the fungal inoculum may be admixed with or applied concurrently with various adjuvants for various purposes.
• an anti-transpirant to inhibit desiccation
• materials which act as stickers and/or nutrients may be used to ensure or sustain germination and provide a conducive environment for growth.
• Carboxymethylcellulose is preferred for these purposes, although a variety of materials may also be used.
• Trichaptum biforme has in the past also been referred to as Polyporus pargamenus and Hirschioporus pargamenus, see Gilbertson et al., "North American Polypores,” Vol. 2, Fungiflore, Oslo, Norway 1987, pages 770-772 and Otjen et al., "Selective Delignification of Birch Wood (Betula papyrifera) by Hirschioporus pargamenus in the Field and Laboratory", Holzaba 40 (1986), 183-189.
• Phanerochaete gigantea has also been known in the past as Peniophora gigantea, see Burdsall, H. H., Jr., "A Contribution to the Taxonomy of the Genus Phanerochaete"., Mycological Memoir, No. 10, J. Cramer publishers, Braunschweig, Germany (1985).
• the white/colorless growing fungi to be used in the invention are those which will grow and reduce the pitch content of the wood to be protected. Those which are particularly good pitch degraders are generally preferred.
• the ability of a fungus to reduce pitch may be determined in various ways, but for purposes of this invention can be determined on sterilized woods samples in the form of wood chips by spraying the chips with a dilute aqueous inoculum of the fungus at a dosage of 10 10 CFUs per kilogram of chips followed by accumulating the chips in a pile under laboratory conditions and allowing the fungus to grow on the chips at room temperature (20° C.) for 14 days. A control involving a water spray is also maintained.
• pitch and "resin” with reference to wood are recognized to indicate extractable wood components of various types involving a complex mixture of hydrophobic substances including without limitation terpenes, the diterpene (“resin”) acids, fatty acids and esters, glycerides, sterols and waxes and components associated therewith such as alcohols.
• the pitch content of substrates is determined in accord with the standard TAPPI Procedure T204 OM-88 and may be expressed as mg. of pitch content per gram of substrates which had been extracted with DCM (a.k.a. methylene chloride).
• DCM a.k.a. methylene chloride
• the treated chips are dried overnight at 60° C. and then ground into sawdust using a Thomas-Wiley Mill with a 10-mesh screen (10 gauge wire screen). Three (3) grams of dried sawdust are combined with about 30 ml. of DCM and the resulting mixture agitated overnight (about 15 hours) at room temperature.
• the liquid medium is pipetted from the mixture, filtered through a 0.45 micron organic filter, the liquid allowed to evaporate at room temperature overnight (for about 15 hours) in a preweighed dish and the residue oven-heated at 60° C. for 30 minutes to further remove DCM.
• the weight of the residue is determined in mg. as the pitch content and expressed either as mg. of pitch content per gram of substrate or as a percentage of pitch in original the substrate (% extractives).
• Pitch reduction is generally indicated when the inoculated fungus show a statistically significant reduction in pitch content compared with the control.
• the pitch is reduced at least 10%, and more preferably at least 15% compared to the control.
• Fungi used in the laboratory study consisted of a colorless strain of O. piliferum, herein D97, and three wild type blue stain fungi (O. piliferum, O. piceae, and O. minus).
• the blue stain fungi were obtained from Pinus species in the north Central United States.
• To inoculate logs cultures were grown in 2% malt extract broth for 14 days prior to inoculation in order to allow fungal mat formation. A dewatered fungal mat was used to inoculate each log end.
• mats which were not used in inoculations were dried and weighed. Averaged dry mat weights were as follows; D97 0.105 g +/-0.009; O. piliferum 0.093 g +/-0.008; O. piceae 0.086 g +/-0.013; and O. minus 0.043 g/-0.002.
• Log ends were inoculated by placing one fungal mat on each end of the red pine log. Fungal mats were evenly spread over the entire end of the log using a sterile glove pressed firmly enough to insure adherence. Simultaneous inoculation of two fungi involved mixing both mats by hand in a beaker, vortexing for 20 seconds, and placing them on the log end.
• logs were stored at room temperature in clear plastic bags with two moist paper towels for 14 weeks. Every three weeks after inoculation the bags were opened to allow air exchange. Sampling and analysis of logs was carried out six and fourteen weeks after inoculation, with four logs sampled at each interval. Logs were flamed on both ends and split with a sterile ax. The right half of the log was used for isolations, with a set pattern which would allow identification of the colonization and distance of fungal growth.
• Colonization percentages were determined by dividing the number of each fungal colony obtained by the total number of isolation attempts per log (average of 22 small chips), and represented samples taken at intervals up to a distance of 15.2 cm into the sapwood from the end.
• Phanerochaete gigantea (NRRL 21054) is evaluated in the place of the D97 fungus.
• O. minus was omitted as was the inoculation of NRRL 21054 two weeks after inoculation with the blue staining fungi.
• Results indicated essentially the same ability of Phanerochaete gigantea to protect the wood against the staining fungi as is shown for D97 in Tables 2 and 3, above.
• Treatments consisted of a water control, an anti-transpirant, D97 at a concentration of 5.1 ⁇ 10 7 CFU/ml with an anti-transpirant, D97 treatment at 5.1 ⁇ 10 7 CFU/ml, and D97 at 5.1 ⁇ 10 6 CFU/ml.
• the anti-transpirant used to retain moisture of the log surfaces was Foreevergreen® (Mycogen Corporation, San Diego Calif.).
• Forevergreen® treatments consisted of 202 ml diluted with 1420 ml water.
• D97 was added to 1420 ml of distilled water, mixed, and sprayed with a hand sprayer with a pressure of 30-40 p.s.i. Each log was individually sprayed including bark and sawn ends until slight runoff. The thirteen inoculated logs were then piled into a pyramidal shape. The anti-transpirant treatments were inoculated immediately after the D97 inoculation or water used for control treatments.
• D97 treatments including, D97 at 5.1 ⁇ 10 6 CFU, D97 at 5.1 ⁇ 10 7 CFU and D97 with an anti-transpirant, were added in order to examine the effect that inoculation time had on sapwood colonization by D97 and blue stain fungi. Inoculation of logs occurred 1 to 2 days, 2 weeks and 4 weeks after cutting. Sampling and analysis of logs occurred as listed above, see Example A and Table 5, below.
• Colonization of blue stain fungi from the sapwood yielded percentages of 63, 63, 0, 8, and 8% for control, anti-transpirant alone, D97 at 5.1 ⁇ 10 6 , D97 at 5.1 ⁇ 10 7 , and D97 with anti-transpirant treatment, respectively (Table 4). A significant difference in colonization of blue stain fungi, was observed between treated and untreated logs.
• the percent sapwood colonized by blue stain fungi was 29, 71, 0, and 4% for control, anti-transpirant, D97 (5.1 ⁇ 10 7 ), and D97 with an anti-transpirant (Table 4). No significant difference was observed between control logs and D97 treated logs, but a significant difference was observed between anti-transpirant and D97 treated logs.
• Percent sapwood colonized was determined when inoculations took place 1-2 days after falling off the trees, 2 weeks after falling and 4 weeks after the falling, with blue stain fungi (wild type O. piliferum, O. piceae and O. minus) being inoculated over D97 4 weeks after cutting.
• results showed colonization percentages of blue stain fungi increase as the time of inoculation increased from 1-2 days to 4 weeks after cutting. Colonization percentages increased for blue stain fungi from 0 to 33%, 8 to 50%, and 8 to 29% for treatments of D97 (5.1 ⁇ 10 6 ), D97 (5.1 ⁇ 10 7 ) and D97 with an anti-transpirant, respectively.
• D97 colonization percentages decreased as the inoculation time increased from 1-2 days to 4 weeks after cutting.
• D97 percentages decreased from 100 to 54%, 100 to 42%, and 96 to 38% for treatments D97 (5.1 ⁇ 10 6 ), D97 (5.1 ⁇ 10 7 with an anti-transpirant, respectively.
• Greatest inhibition of blue stain fungi and maximum colonization of D97 in sapwood was obtained when inoculation occurred 1 to 2 days after cutting.
• the fungi used in this invention are indicated to grow white and/or colorless.
• Fungi such as white rot fungi generally grow largely or essentially white.
• fungi such as Ophiostoma and members of the class to which it belongs may grow white or have white portions, but also may have substantial colorless portions and may even grow essentially colorless, not only at the surface, but particularly within wood which they penetrate.
• detection is often not readily ascertained and close examination may be required. Any white residue left by any fungi used herein is usually minor and in any event is not considered a stain for purposes of this invention.
• fungi of the classes Ascomycetes and Deuteromycetes which grow largely or essentially colorless can be preferred aesthetically for use herein for such colorless growth.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Forests & Forestry (AREA)
• Microbiology (AREA)
• Micro-Organisms Or Cultivation Processes Thereof (AREA)
• Debarking, Splitting, And Disintegration Of Timber (AREA)

Priority Applications (9)

Applications Claiming Priority (1)

Related Child Applications (1)

Publications (1)

Family

ID=22933695

Family Applications (2)

Family Applications After (1)

Country Status (8)

Cited By (3)

Families Citing this family (2)

Citations (3)

Family Cites Families (3)

• 1994
  • 1994-05-20 US US08/247,131 patent/US5532164A/en not_active Expired - Lifetime
• 1995
  • 1995-04-17 US US08/424,134 patent/US5518921A/en not_active Expired - Lifetime
  • 1995-05-19 BR BR9502485A patent/BR9502485A/pt not_active Application Discontinuation
  • 1995-05-19 CA CA002149808A patent/CA2149808A1/en not_active Abandoned
  • 1995-05-22 DE DE69522602T patent/DE69522602T2/de not_active Expired - Fee Related
  • 1995-05-22 JP JP7122523A patent/JPH0852708A/ja active Pending
  • 1995-05-22 ZA ZA954139A patent/ZA954139B/xx unknown
  • 1995-05-22 EP EP95107843A patent/EP0683023B1/en not_active Expired - Lifetime
  • 1995-05-22 FI FI952488A patent/FI952488L/fi not_active Application Discontinuation

Patent Citations (3)

Non-Patent Citations (12)

Also Published As

Similar Documents

Legal Events